Telephone system.



G. W. MoGONIGLE..

TELEPHONE SYSTEM.

APPLICATION FILED JULY 15, 1912.

1,076,990. I Patented Oct. 28, 1913.

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TELEPHONE SYSTEM.-

Specification of Letters Patent.

Patented Oct. 28, 1913.

Application filed m 15, 1912. Serial No. 709,459.

To all whom it may concern. 4 x

Be it known that LCHARL S W. MGGONP one, a citizen of the United States, residing at Algona, in the county of King and State of ivashington, have invented certain new and useful Improvements in Telephone Systems, of which the following is aspecifi= cation.

This invention relates to telephone apparatus and particularly where the same is operated on a wire or wires of a telephone system and where the various currents passing thereover have a disturbing influence upon the voice sounds of the telephone.

The object of the present invention is, first, to afford a telephone current of rela-- tively low potential by preventing the currents of high resistance receiying'instrin ments being cut into the line by including in the line a high frequency transformer primary coil of small ohmic resistancy and utilizing the secondary coil of the trans former with a telephone receiver of high resistance; second, to afford means whereby the induction current of higher frequency than voice sounds will pass through a con denser provided in a shunt across the primary of the high frequency transformer, as

such resistance offers less resistance than a coil to high frequencies; third, to provide a path for frequencies lower than that generated by voice sounds and with less resistance to such currents than the relatively high resistance offered by a telephone receiver and condenser; fourth, to provide means for sending a preliminary signal, as the ringing of a bell; and fifth, to provide means for cutting into the main line of the secondary terminals of a telephone induction-coil when speaking and cutting the same out when re ceiving a telephone message.

With these and other ends in view, the invention consists in the novel arrangement and adaptation of parts, as will be hereinafter described and claimed.

The accompanying drawing is a diagram illustrating an embodiment of my inven tion.

The reference numerals 11 designate an electric transmission line, or main line, having therein the primary coil 3 of a high frequency air core transformer. 4: repre sents a condenser provided in a shunt ex tending between the terminals of said coil. 5 is the secondary coil of said transformer whose terminals are connected to wires 6 and 7 and constitute a normally incomplete circuit with a gap between the terminals 6' and 7 thereof. Included in the circuit is a telephone receiver R and a condenser S. An impedance coil 9 having a movable iron core 9 shunted between the wires (5 and 7 as indicated in the View. 6 and 7 are branches to the respective wires of said circuit and are provided with terminals 6" and T which are disposed to be engaged by the members 10 and 11 of a bipolar switch which are connected to the heliX of the magnet 12 of a high resistance telephone receiver. The diaphragm 12" of this receiver is operatiyely connected with a lever 13 having its short arm pivoted to; an element 14-, while its long arm carries a finger 13 to cooperatewith a quantity of mercury provided in a cup 15. The latter is supported by an adjustable screw 1'6 extending through a screw threaded hole in a fixed element 17 A battery 18 and a signal bell 19, or an equivalent, are provided in a local, or relay, circuit which includes wires 20, and whereof the finger 13 and said mercury serve as the terminals. The above described parts constitute the re ceiving portion of a telephone system. The sending portion thereof consists of a telephone transmitter T and a battery 21 upon the circuit of an induction coil 22 of a transformer, the other coil of which is shunted with said main line to bridge a gap therein when the closure 23 for the same is open.

In operation, the main line closure 23 is opened when the transmitter T is to be employed and is in its normally closed position at all other. times. When the message is to be delivered to the receiver, an induced current passes from coil 5 through the circuit wire 6, branch 6 switch member 10, helix of the receiver magnet 12 to actuate the diaphragm 12, whereupon the lever 13 is influenced by vibratory movements to cause the lever finger 13 to be dipped into the mercury and thereby close the relay circuit and effect the ringing of the signal bell 19. The switch is then swung into position indicated by broken lines to present the switch member 10 into position indicated by 10 to close the gap between the terminals 6 and 7 of the circuit of the telephone receiver R whereupon the latter is in circuit and rendered operable.

The aforedescribed system is primarily intended for use with a single wire ground return circuit, but it may obviously be used on a complete metallic circuit.

Among the advantages of the invention, are that remote instruments will receive as distinct and loud communications as those closer to the sending instrument, and it may be used for the transmission of a number of concurrent conversations over a single main line by the provision of widely different induction coils for the various transmitters and the use of high frequency alternating current in the primary circuit of the transmitters and by carefully adjusting the respective condensers and impedance coils.

l/Vhat I claim, is

1. In a telephone system, the combination with the main line embracing the primary coil of a transformer, a normally incomplete circuit embracing the secondary coil of said transformer, and a telephone receiver and a condenser on said circuit, of a normally incomplete relay circuit, a signal instrument in the latter, a shunt circuit embracing the magnet of a high resistance telephone receiver, a diaphragm for this receiver, a closure for the opening in said relay circuit, operatively connected with said diaphragm,

a switch adapted to be selectively employed for closing said incomplete circuit or for conductively connecting said relay circuit with the first named circuit.

2. In a telephone system, the combination with the main line embracing the primary coil of a transformer, a shunted condenser between the terminals of said primary coil, a normally incomplete circuit embracing the secondary coil of said transformer, and a telephone receiver and a condenser on said circuit, of a normally incomplete relay circuit, a signal instrument in the latter, a shunt circuit embracing the magnet of a high resistance telephone re ceiver, a diaphragm for this receiver, a closure for the opening in said relay circuit, cperatively connected with said diaphragm, a switch. adapted to be selectively employed for closing said incomplete circuit or for conductively connecting said relay circuit with the first named circuit.

Signed at Seattle, lVashington, this 6th day of July 1912.

CHARLES W. MOGONIGLE.

Witnesses:

PIERRE BARNES, J. V. VVOODWARD.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. G. 

